video: Versatile Express DVI output driver

Versatile Express' DVI video output can be connected to one the three
sources - motherboard's CLCD controller or a video signal generated
by one of the daughterboards.

This driver configures the muxer FPGA so the output displays content
of one of the framebuffers in the system (0 by default, can be changed
by user writing to the "fb" sysfs attribute of the muxfpga device).

It will also set up the display formatter mode and keep it up
to date with mode changes requested by the user (eg. with fbset
tool).

Signed-off-by: Pawel Moll <pawel.moll@arm.com>

2 files changed, 223 insertions, 0 deletions

diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index 9df387334cb..646075279d6 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -175,3 +175,6 @@ obj-$(CONFIG_DISPLAY_TIMING) += display_timing.o
 obj-$(CONFIG_OF_DISPLAY_TIMING) += of_display_timing.o
 obj-$(CONFIG_VIDEOMODE) += videomode.o
 obj-$(CONFIG_OF_VIDEOMODE) += of_videomode.o
+
+# platform specific output drivers
+obj-$(CONFIG_VEXPRESS_CONFIG)	  += vexpress-dvi.o
diff --git a/drivers/video/vexpress-dvi.c b/drivers/video/vexpress-dvi.c
new file mode 100644
index 00000000000..f08753450ee
--- /dev/null
+++ b/drivers/video/vexpress-dvi.c
@@ -0,0 +1,220 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Copyright (C) 2012 ARM Limited
+ */
+
+#define pr_fmt(fmt) "vexpress-dvi: " fmt
+
+#include <linux/fb.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/vexpress.h>
+
+
+static struct vexpress_config_func *vexpress_dvimode_func;
+
+static struct {
+	u32 xres, yres, mode;
+} vexpress_dvi_dvimodes[] = {
+	{ 640, 480, 0 }, /* VGA */
+	{ 800, 600, 1 }, /* SVGA */
+	{ 1024, 768, 2 }, /* XGA */
+	{ 1280, 1024, 3 }, /* SXGA */
+	{ 1600, 1200, 4 }, /* UXGA */
+	{ 1920, 1080, 5 }, /* HD1080 */
+};
+
+static void vexpress_dvi_mode_set(struct fb_info *info, u32 xres, u32 yres)
+{
+	int err = -ENOENT;
+	int i;
+
+	if (!vexpress_dvimode_func)
+		return;
+
+	for (i = 0; i < ARRAY_SIZE(vexpress_dvi_dvimodes); i++) {
+		if (vexpress_dvi_dvimodes[i].xres == xres &&
+				vexpress_dvi_dvimodes[i].yres == yres) {
+			pr_debug("mode: %ux%u = %d\n", xres, yres,
+					vexpress_dvi_dvimodes[i].mode);
+			err = vexpress_config_write(vexpress_dvimode_func, 0,
+					vexpress_dvi_dvimodes[i].mode);
+			break;
+		}
+	}
+
+	if (err)
+		pr_warn("Failed to set %ux%u mode! (%d)\n", xres, yres, err);
+}
+
+
+static struct vexpress_config_func *vexpress_muxfpga_func;
+static int vexpress_dvi_fb = -1;
+
+static int vexpress_dvi_mux_set(struct fb_info *info)
+{
+	int err;
+	u32 site = vexpress_get_site_by_dev(info->device);
+
+	if (!vexpress_muxfpga_func)
+		return -ENXIO;
+
+	err = vexpress_config_write(vexpress_muxfpga_func, 0, site);
+	if (!err) {
+		pr_debug("Selected MUXFPGA input %d (fb%d)\n", site,
+				info->node);
+		vexpress_dvi_fb = info->node;
+		vexpress_dvi_mode_set(info, info->var.xres,
+				info->var.yres);
+	} else {
+		pr_warn("Failed to select MUXFPGA input %d (fb%d)! (%d)\n",
+				site, info->node, err);
+	}
+
+	return err;
+}
+
+static int vexpress_dvi_fb_select(int fb)
+{
+	int err;
+	struct fb_info *info;
+
+	/* fb0 is the default */
+	if (fb < 0)
+		fb = 0;
+
+	info = registered_fb[fb];
+	if (!info || !lock_fb_info(info))
+		return -ENODEV;
+
+	err = vexpress_dvi_mux_set(info);
+
+	unlock_fb_info(info);
+
+	return err;
+}
+
+static ssize_t vexpress_dvi_fb_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", vexpress_dvi_fb);
+}
+
+static ssize_t vexpress_dvi_fb_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	long value;
+	int err = kstrtol(buf, 0, &value);
+
+	if (!err)
+		err = vexpress_dvi_fb_select(value);
+
+	return err ? err : count;
+}
+
+DEVICE_ATTR(fb, S_IRUGO | S_IWUSR, vexpress_dvi_fb_show,
+		vexpress_dvi_fb_store);
+
+
+static int vexpress_dvi_fb_event_notify(struct notifier_block *self,
+			      unsigned long action, void *data)
+{
+	struct fb_event *event = data;
+	struct fb_info *info = event->info;
+	struct fb_videomode *mode = event->data;
+
+	switch (action) {
+	case FB_EVENT_FB_REGISTERED:
+		if (vexpress_dvi_fb < 0)
+			vexpress_dvi_mux_set(info);
+		break;
+	case FB_EVENT_MODE_CHANGE:
+	case FB_EVENT_MODE_CHANGE_ALL:
+		if (info->node == vexpress_dvi_fb)
+			vexpress_dvi_mode_set(info, mode->xres, mode->yres);
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block vexpress_dvi_fb_notifier = {
+	.notifier_call = vexpress_dvi_fb_event_notify,
+};
+static bool vexpress_dvi_fb_notifier_registered;
+
+
+enum vexpress_dvi_func { FUNC_MUXFPGA, FUNC_DVIMODE };
+
+static struct of_device_id vexpress_dvi_of_match[] = {
+	{
+		.compatible = "arm,vexpress-muxfpga",
+		.data = (void *)FUNC_MUXFPGA,
+	}, {
+		.compatible = "arm,vexpress-dvimode",
+		.data = (void *)FUNC_DVIMODE,
+	},
+	{}
+};
+
+static int vexpress_dvi_probe(struct platform_device *pdev)
+{
+	enum vexpress_dvi_func func;
+	const struct of_device_id *match =
+			of_match_device(vexpress_dvi_of_match, &pdev->dev);
+
+	if (match)
+		func = (enum vexpress_dvi_func)match->data;
+	else
+		func = pdev->id_entry->driver_data;
+
+	switch (func) {
+	case FUNC_MUXFPGA:
+		vexpress_muxfpga_func =
+				vexpress_config_func_get_by_dev(&pdev->dev);
+		device_create_file(&pdev->dev, &dev_attr_fb);
+		break;
+	case FUNC_DVIMODE:
+		vexpress_dvimode_func =
+				vexpress_config_func_get_by_dev(&pdev->dev);
+		break;
+	}
+
+	if (!vexpress_dvi_fb_notifier_registered) {
+		fb_register_client(&vexpress_dvi_fb_notifier);
+		vexpress_dvi_fb_notifier_registered = true;
+	}
+
+	vexpress_dvi_fb_select(vexpress_dvi_fb);
+
+	return 0;
+}
+
+static const struct platform_device_id vexpress_dvi_id_table[] = {
+	{ .name = "vexpress-muxfpga", .driver_data = FUNC_MUXFPGA, },
+	{ .name = "vexpress-dvimode", .driver_data = FUNC_DVIMODE, },
+	{}
+};
+
+static struct platform_driver vexpress_dvi_driver = {
+	.probe = vexpress_dvi_probe,
+	.driver = {
+		.name = "vexpress-dvi",
+		.of_match_table = vexpress_dvi_of_match,
+	},
+	.id_table = vexpress_dvi_id_table,
+};
+
+static int __init vexpress_dvi_init(void)
+{
+	return platform_driver_register(&vexpress_dvi_driver);
+}
+device_initcall(vexpress_dvi_init);